Various semiconductor manufacturing processes utilize cluster tools having multiple load lock chambers. In some embodiments, the multiple load lock chambers are stacked vertically. However, such a configuration presents a limited physical space for providing access to the chambers for certain facilities, particularly for the upper chamber of the stacked chambers. For example, the inventors have observed that uniform pumping around a substrate disposed within the upper load lock chamber may be negatively impacted by the configuration of the pump port and other physical components within the chamber due to the lack of vertical space to configure the process chamber.
Accordingly, the inventors have provided an improved apparatus for uniformly pumping within stacked process chambers or in other chambers where limited physical space may be an issue.